Tdc ???

[akart]

First let me say that the truck runs perfect. I am adding a Voodoo cam and a bunch of other stuff. I start and check the TDC and with the timing marks lined up on the cam and crank (cam down and crank up) the compression stroke is on cyl #6. Me thinks the cam is 180 off. I am thinking I will install the new DUI distributor the same way (as is) Is this OK, any thoughts. If I install the distributor 180 from what it is the compression stroke at TDC will still be at #6 (I think)

[geezer#99]

Your cam's installed right.
Chevy engineers designed it that way for accurate assembly line procedure. Dot to dot is easier to line up quickly than both dots at 12 oclock.
When you put the new cam in just line the dots up with cam at 6 oclock and crank gear at 12 which is #6 tdc compression. Rotate the crank once and you'll be at #1 tdc compression. DRop your dizzy in with the rotor pointing at #1 and you're good to go.
Since you'll be adjusting the lifters for pre-load (and rotating the crank several times) just install the timing cover last. Check the dots are at 12 and 12 as your final check and bolt it togethor.
Here's a link.
http://www.crankshaftcoalition.com/w...op_dead_center

[SkinnyG]

The camshaft will be 180° out every other rotation - it turns half crankshaft speed since you only get one valve event every two revolutions. Fuggedaboudit. Just make sure spark happens at #1 compression.